裂缝性致密砂岩气藏时变形状因子研究

发布时间：2019-03-22 06:10

【摘要】：形状因子是裂缝性致密砂岩气藏产能模拟分析的重要参数,但研究多集中在常规油气藏中,超低渗透率致密砂岩气藏的形状因子研究尚未开展。通过对Ehsan模型进行改进,运用数值计算方法得到了一维径向基质—裂缝模型时变形状因子,研究了渗透率、孔隙度、基质尺寸对时变形状因子的影响,并运用室内实验对该模型进行验证。结果表明:由于压力在超低渗透率(k10~(-5)×10~(-3)μm~2)基质中传递较慢,超低渗透率致密砂岩气藏形状因子出现明显的3个不同阶段:基质外边界压力下降阶段,基质内边界压力下降阶段,形状因子向稳定过渡阶段。随着渗透率和孔隙度的降低,第一、二阶段所持续时间增加,气体生产时间同时增加。随着基质尺寸的增加,形状因子达到稳定的整体时间增加,但各阶段所持续时间的相对关系未发生变化。通过数值模拟结果与实验结果对比发现,发现运用改进Ehsan模型计算得到的形状因子能够对致密砂岩气藏生产进行较好的预测。它可以为超低渗致密砂岩气藏的产能预测提供更准确的理论方法,也可为试井解释提供合适的形状因子、计算合理的窜流系数。
[Abstract]:The shape factor is an important parameter for productivity simulation analysis of fractured tight sandstone gas reservoirs, but most of the studies are concentrated in conventional reservoirs, and the study of shape factors of ultra-low permeability tight sandstone gas reservoirs has not been carried out. Through the improvement of Ehsan model, the time-varying shape factor of one-dimensional radial matrix-fracture model is obtained by using numerical calculation method. The effects of permeability, porosity and matrix size on time-varying shape factor are studied. The model is verified by laboratory experiments. The results show that due to the slow transfer of pressure in ultra-low permeability (k10 ~ (- 5) 脳 10 ~ (- 3) 渭 m ~ (- 2) matrix, the shape factor of ultra-low permeability tight sandstone gas reservoir appears three distinct stages: the pressure drop stage of the outer boundary of the matrix; The matrix boundary pressure drop stage, shape factor to stable transition stage. With the decrease of permeability and porosity, the duration of the first and second stages increases and the gas production time increases at the same time. With the increase of the size of the matrix, the overall time for the shape factor to reach stability increases, but the relative relationship of the duration of each stage does not change. By comparing the numerical simulation results with the experimental results, it is found that the shape factor calculated by the improved Ehsan model can be used to predict the production of tight sandstone gas reservoirs. It can provide more accurate theoretical method for productivity prediction of ultra-low permeability tight sandstone gas reservoir, and can also provide suitable shape factor for well test interpretation, and calculate reasonable cross-flow coefficient.
【作者单位】：中国石油大学(华东)石油工程学院;中国石油集团川庆钻探工程有限公司井下作业公司;卡尔加里大学化学与石油工程学院;
【基金】：国家科技重大专项(编号:2016ZX05023-001;2017ZX05049-006) 国家重点基础研究发展计划(973计划)项目(编号:2014CB239103) 国家自然科学基金项目(编号:51674279)联合资助
【分类号】：P618.13

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